In known timepieces, the date display is formed by a disc, generally toothed on the interior, which moves facing an opening and which is driven over a 24 hour period by a reducing gear wheel train, itself operated via the dial train by an electromagnetic motor of the stepping motor type having a bipolar magnet.
This type of drive thus requires the arrangement of a special wheel train meshing with the dial train. Such wheel train generally includes at least one specific driving wheel which is provided, on the one hand, with standard outer teeth receiving a motor couple from said dial train and which, on the other hand, is provided with an elastic arm which engages with the date disc.
Such arm is adapted so as to be able to absorb rapid displacements forward or backward from the date disc during rapid correction effected by the user through the time setting crown.
Otherwise, in addition to such first driving means which enable normal displacement of the date disc, such arrangement requires having available other driving means formed by a special correction mechanism including, for example, a sliding pinion cooperating with an intermediate wheel capable of bringing about the rapid correction mentioned hereinabove with the help of the crown.
Such arrangement is thus complex, clumsy and costly.
Furthermore, it is relatively fragile being given that certain manipulations such as rapid correction and correction via the dial train in the neighbourhood of midnight can abnormally stress and damage the elastic arm of the driving wheel operating the date disc.
Otherwise, since it is driven in rotation in a permanent manner by the dial train, the wheel train of the first driving means creates a substantial resistive load on the dial train, even though the date disc need be displaced in normal operation only once every twenty-four hours.
Furthermore, the data disc must be perfectly positioned relative to the opening following each displacement so that the disc generally cooperates with a jumper spring which increases in a significant manner the resistive couple.
Thus, the present invention has as purpose to overcome these drawbacks in furnishing a timepiece including display means such as a date display operated by driving means permitting the simplification of the overall conception of such timepiece by diminishing the number of its components, its dimensions and the applied load.